Remove the mower blades and look for problems such as a thin trailing edge, bends, dents or cracks.
TIP If there’s nothing obvious take the blade to a hardware store and compare it to a new one.
THIN TRAILING EDGE The edge opposite the cutting edge is called the trailing edge and is often slanted upward to create an updraft for lifting grass and clippings. Dust and sand can wear it down so when it becomes thin the blade needs replacing.
DENTS OR CRACKS If there’s obvious erosion from wear and sharpening and the cutting edge can’t be filed smooth the blade should be replaced.
BENT BLADE Check the blade by laying it on a work bench to see if there are kinks or obvious bends. Compare it to a new one to be certain.